When an electromagnetic wave encounters an object or a boundary, several things can happen depending on the properties of the object and the characteristics of the wave.
Reflection: Reflection occurs when an electromagnetic wave strikes a surface and bounces back. The angle of incidence (the angle at which the wave hits the surface) is equal to the angle of reflection (the angle at which the wave bounces off). Reflected waves can retain their original form and energy, resulting in a mirror-like reflection, or they can be scattered in various directions, such as with rough or irregular surfaces.
Transmission: Transmission occurs when an electromagnetic wave passes through an object without being absorbed or reflected. The extent to which a wave can transmit through a material depends on the properties of the material, including its transparency and the frequency of the wave. Transparent materials, like glass or air, allow most of the wave to pass through, while opaque materials, like metal, block the wave entirely.
Absorption: Absorption occurs when an electromagnetic wave transfers some or all of its energy to the object it encounters. The absorbed energy can cause various effects, such as heating the object or exciting its electrons. Different materials have different absorption properties, meaning they may selectively absorb certain frequencies or wavelengths of electromagnetic radiation.
Scattering: Scattering happens when an electromagnetic wave interacts with small particles or irregularities in an object. The wave is redirected in different directions, often changing its intensity or wavelength. Scattering is responsible for phenomena such as diffuse reflection (scattering of light in all directions) or the blue color of the sky (scattering of shorter-wavelength blue light by molecules in the Earth's atmosphere).
It's important to note that these processes can occur simultaneously or in combination when an electromagnetic wave interacts with an object or a boundary. The nature of the interaction depends on the properties of the object and the characteristics of the wave, including its frequency, intensity, and polarization.